1. Field of the Invention
The present invention is directed to routing data in networks. It particularly concerns effectively routing data between two or more Mobile Ad-hoc Networks (MANETs) networks with different routing protocols, including, but not limited to, link-state or distance vector protocols.
2. Background Information
In recent years, there has been a large increase in the use of communication networks which are self-forming and self-configuring. Mobile ad hoc networks (MANETs) or disruption tolerant networks (DTNs) are an example of such networks. They include mobile nodes which communicate wirelessly and are free to move about, such that at a given point in time, wireless connectivity in the form of a multi-hop or multi-link graph or an “ad hoc” network exists between the mobile nodes.
A MANET is beneficial for self-forming, self-configuring, and self-healing operation, i.e., operation in an environment where the media and communications channels undergo frequent changes (e.g., over free space, optical, radio-frequency (RF), underwater acoustic links) and where nodes in a network freely enter and leave the network. Typically, the mobile nodes in a MANET will form a link, i.e., a wireless communication path, and exchange data packets and routing information through the link if they are within a suitable communication range.
MANETs are generally characterized by dynamic network topologies, bandwidth- and energy-constrained operation, variable capacity links between nodes in the network, and limited network security. MANETs are different from wired networks in at least two ways. First, mobile nodes in MANETS are typically dependent on batteries for power. Each transmission and receipt of data requires power. This power consumption sharply increase the importance of reducing the number of transmissions needed to direct a packet to its final destination. It is important to be able to route packets efficiently through the network, thereby reducing the cost associated with transmitting a message. Second, because of a frequently-changing network topology, routing information can rapidly become stale. Nevertheless, new MANET systems are being increasingly deployed, especially for military applications.
In many MANETs or DTNs, network nodes generally operate under bandwidth- and energy constraints. As noted above, nodes have limited power available for receiving and transmitting messages. In addition, links or connections in the network change frequently. In environments in which two or more MANETs exist, significant efficiency gains are frequently missed due to the networks failure to share routing information effectively. For instance, the most cost-efficient, for example, the fastest or lowest energy-consuming or lowest bandwidth-consuming route for a data packet may involve efficiently routing the data packet from a node in one of the MANETs through a node in the second, different MANET. Such routing may require the MANETs to share network routing information. However, current MANETS typically only provide for limited sharing of network routing information between the MANETs. This is a result, in part, of MANETs in some instances utilizing, mutually incompatible routing protocols.
This lack of shared routing information prevents multiple interconnected yet independent MANETs (e.g., MANETs operated by different entities and/or with different routing protocols) to efficiently route data packets to one another, thereby achieving the benefits of a single larger MANET.